Thermostatic controller



July 28, 1942. A. A. KR-AEUTER THERMOS TAT I C CONTROLLER Filed Nov. 30, 1940 l v NTOR a. BY W fiTTQiQNEY Patented July 28, 1942 UNITED. STATES PATENT OFFICE THERMOSTATIC CONTROLLER Arthur A. Kraeuter, Maplewood, N. J.

Application November 30, 1940, Serial No. 367,968

4 Claims.

This invention relates to a fire alarm of the fluid pressure or rate-of-rise type, and one object 'of 'the invention is 'to provide a novel and improved unit which'may be mounted on the ceiling or a wall of the room and itself serve as a firedetecting and signal initiating device or which may be combined with a fire detecting loop of tubing which passes through an area to be protected against fire.

Another object is to provide a thermostatic controller for fire detecting and signal initiating unit of this character wherein all of the movable parts, electrical contacts, etc., shall be enclosed within a substantially dust-proof and moisture proof casing, whereby the possibility of inoperativeness of the unit through accumulations of dirt and moisture, shall be reduced to the minimum.

A further object is to provide a thermostatic controller that shall comprise a novel and improved construction and combination of a casing, and a pressure actuated electric circuit controller including electrical contacts, whereby the unit shall be sensitive to small rises in temperature in the vicinity of the unit and shall be reliable and durable in operation.

Other objects, advantages and results of the invention will appear from the following description in conjunction with the accompanying drawing in which Figure 1 is a vertical longitudinal sectional View through a fire detecting and signal initiating unit embodying my invention showing the signal circuits diagrammatically.

Figure 2 is a top plan view of the unit from the line 2-2 of Figure 1.

Figure 3 is an enlarged vertical sectional view through the breather or vent for the air chamber, and

Figure 4 is a fragmentary vertical sectional view showing a modification of the invention.

My fire detecting and signal initiating unit is shown as comprising a casing A that includes a plate I formed of suitable electrical insulating material such as fiber, Bakelite and the like, upon one side of which is secured a housing 2 preferably of thin metallic, heat and electricity conductive walls. The housing has one open end provided with a flange 3 that is in abutting contact with the plate I and has a rim 4 seated in r a groove 5 in the plate to form a substantially dust and moisture proof connection of the housing with the plate. Preferably the rim 4 is embedded in some suitable plastic sealing material 50 to enhance the dust and moisture proof properties of the joint. The housing 2 is secured to the plate in any suitable manner preferably by bolts 6 that pass through the plate and the flange 3.

Within the housing 2 is a transverse partition I that divides the interior of the housing into two compartments 8 and 9, the former of whichserves as an air chamber. A pressure actuated signal initiating device that is shown in the form of a known type of diaphragm Ill, is mounted on the partition 1 Within the other compartment 9 and is responsive to air pressure in the chamber 8 through a passage II. The diaphragm I0 carries an electrical contact member I2 which cooperates with another contact member I3 that is in the form of a screw threaded in and passing through the plate I with one end extending into the chamber 9 into cooperative relation with the contact member I2.

The contact member I2, through the diaphragm I 3 and partition I, is electrically connected to the housing 2, and the housing is electrically connected to a wire 260 so as to form a part of the signal circuit which also includes a source B of electricity and an audible or visible signal such as a bell C having one terminal connected to the source B of electricity and. the other terminal connected to the contact member I3.

With the construction so far described, when a rise in temperature occurs in the Vicinity of the housing 2 the air within the chamber 8 is expanded so as to increase the pressure within the chamber and expand the diaphragm I 6 to cause the contact member I2 to contact with the contact member I3 and close the circuit and thereby cause actuation of the signal C.

To permit reduction of the pressure in the chamber 8 after the fire has been extinguished, a vent or breather D is mounted in the partition I to establish communication between the chamber 8 and the compartment 9, This vent may be of any suitable construction, but preferably comprises a section H: of a hypodermic needle on which is swaged a coupling I5 that is fused or soldered into the partition I as at I6 whereby 1e passage through the needle I4 will permit escape of air from the chamber t. This passage is so restricted as to prevent rapid escape of air from the chamber 8 upon the occurrence of rises in temperature so as to ensure the necessary building up of pressure in the chamber under the influence of temperature rises.

The chamber 9 is vented to the atmosphere through a duct I! through the plate I.

To reduce to the minimum the possibility of dust and moisture entering the compartment 9 through the duct I1, and also to protect the contact member l3 from dust and moisture, a second housing I8 is secured to the side of the plate I opposite the housing 2 so as to enclose both the duct 1'! and the contact member I3. As shown, the second housing I8 has a flange I9 that is secured to the plate I by the bolts 6, preferably in electrically insulated relation to the housing 2. The wire which connects the contact member I3 in circuit may pass through a dust proof opening 2| in the second housing I8.

It will be understood that there will be sufficient leakage of air between the flange IQ of the second housing and the plate I to permit proper venting of the chamber 8.

For mounting the unit on a support, such as a wall or ceiling E, a bracket strip 22 may be secured to the second housing 18 in any suitable manner, as by soldering or riveting, and has openings 23 to receive fastening members 24.

For testing the unit, I may utilize an electrical heating coil 25 mounted on the wall of the housing in the chamber 8 in insulated relation thereto, with one terminal of the coil grounded on the housing and the other terminal connected to a bolt 26 that is insulated from the housing and is connected in circuit with the source of electricity B and the housing 2. A suitable switch 21 is included in the circuit for controlling the heater 25. To test the unit, it is simply necessary to close the switch 21 which will energize the heater 25 and expand the air in the chamber 8 whereupon, if the system is operative, the signal C will be actuated. Should there be an abnormal air leak in the unit, or some defect in the electrical circuit, the signal will not be operated and trouble in the system thus will be indicated.

Where the unit is to be used by itself, the partition 1 will be located in the housing in the position shown in Figure 1, but where it is intended to use the unit in combination with a loop of fire detecting tubing F as shown in Figure 4, the partition I will be so located as to provide an air chamber of less capacity than that shown in Figure 1. For convenience, the housing may have two internal shoulders 28 and 29 for locating and supporting the partition in the respective positions.

With the form of the invention shown in Figure 4, air in the tubing F will be expanded by a fire in the vicinity of any portion of the tubing, and this expansion will be transmitted to the air chamber in the housing 2 so as to actuate the signal in the manner hereinbefore described.

It will be understood by those skilled in the art that the specific details of structure shown and described are primarily for the purpose of illustrating the principles of the invention and that many modifications and changes may be made in the structural details and the combination and arrangement thereof without departing from the spirit or scope of the invention.

Having thus described my invention what I claim is:

1. A thermostatic controller comprising a plate of electrical insulating material, a casing having heat conductive walls and an open end, means fastening said casing to one side of said plate so that said plate closes said open end of the casing, a partition in said casing providing a compartment between itself and said plate and an air chamber between itself and the other end of said casing, a pressure responsive diaphragm mechanically mounted on said partition within said compartment to be actuated by air pressure in said chamber, a restricted vent in said partition establishing communication between said air chamber and said compartment, a second vent from said compartment through said plate, said diaphragm carrying an electrical contact member in said compartment, a second electrical contact member mounted in and extending through said plate with one end in cooperative relation to the first-mentioned contact member, and a second casing secured to the side of said plate that is opposite the first-mentioned casing and forming between itself and said plate a compartment with which said second vent communicates and within which said second electrical contact member is enclosed.

2. The thermostatic controller set forth in claim 1 wherein said casing, said partition and said diaphragm are electrically conductive and are insulated from said second contact member by said plate.

3. A thermostatic controller comprising a plate of electrical insulating material, a casing having heat conductive walls and an open end, means fastening said casing to one side of said plate so that said plate closes said open end of the casing, a partition in said casing providing a compartment between itself and said plate and an air chamber between itself and the other end of said casing, a pressure responsive diaphragm mechanically mounted on said partition within said compartment to be actuated by air pressure in said chamber, a restricted vent in said partition establishing communication between said air chamber and said compartment, a second vent from said compartment through said plate, said diaphragm carrying an electrical contact member in said compartment, a second electrical contact member mounted in and extending through said plate with one end in cooperative relation to the first-mentioned contact member, said casing, said partition and said diaphragm being electrically conductive and insulated from said second contact member by said plate.

4. The thermostatic controller set forth in claim 1 with the addition of means for securing said second casing on a support whereby said plate and the first-mentioned casing shall be held in spaced relation to said support.

ARTHUR A. KRAEUTER. 

